Field
The invention relates to a coupling assembly for coupling a rod to a bone anchoring element, and to a bone anchoring device with such a coupling assembly. The coupling assembly includes a receiving part and a pressure element located at least partially in an accommodation space of the receiving part. The pressure element has a flexible portion to clamp a head of the bone anchoring element. The pressure element can assume in the receiving part an insertion position where insertion and removal of the head is permitted, a locking position where the head is locked in the receiving part, and a pre-locking position where the head is pivotable but is prevented from removal from the receiving part.
Description of Related Art
US 2010/0234902 A1 describes a receiving part for receiving a rod for coupling the rod to a bone anchoring element, wherein the receiving part includes a receiving part body with a channel for receiving a rod and an accommodation space for the head of a bone anchoring element. The accommodation space has a bottom opening for inserting the head, and a pressure element is at least partially provided in the accommodation space to clamp the head. The pressure element is movable along a longitudinal axis of the receiving part body from an inserting position to insert the head, to a pre-locking position to clamp the head in the receiving part by a pre-stress exerted by the pressure element, and to a locking position to lock the head in the receiving part.